1979 Big Trak from MB

BIG TRAK / bigtrak was a programmable electric vehicle created by Milton Bradley in 1979.

It was a six-wheeled tank with a front-mounted blue photon beam headlamp, and a keypad on top. The toy could remember up to 16 commands which it then executed in sequence (such as “go forward 5 lengths”, “pause”, “turn 30degrees right”, “fire phaser” and so on. There was a “repeat” instruction allowing simple loops, but the language was not Turing complete, lacking branching instructions; the Big Trak also lacked any sort of sensor input other than the wheel sensors.

BigTrak Keypad (US)

There is now a small but dedicated Internet community who have reverse engineered the BIG TRAK and the Texas Instruments TMS1000 microcontroller inside it (see external links).

The US and GB/European versions were noticeably different. The US version was moulded in gray plastic and labelled BIG TRAK whereas the GB version was white and labelled bigtrak with a different keypad.

Bigtrak also included an optional trailer accessory. Once hooked to Bigtrak, this trailer could be programmed to dump its payload.

Programmable keypad

All programming to BigTrak was done through the keypad shown here. There were no LED displays or ways to display program instructions, beyond actually running the program, which was done by pressing “GO”. Other function keys included:

Forward/Backward: Move forward and backward

Left/Right: Turn the specified number of degrees in that direction

HOLD: Pause for a number of seconds (GB version; P: Pause)

FIRE: Fire the LED “laser” (GB; Photon Symbol)

CLR: Clear the program (GB; CM: Clear Memory)

CLS: Clear Last Step (GB; CE; Clear last step)

RPT: Repeat a number of steps (primitive loop) (GB; x2: Repeat key)

TEST: Run short test program

CK: Check last instruction (GB; Tick symbol)

Out: Dump optional trailer accessory

In: Reserved for future expansion (GB; missing. Disabled or not implemented on most if not all BigTraks)